1. Field of the Invention
The invention is related to a device for distributing the pressure of a ski, such as especially an alpine ski, over its gliding surface.
The invention is also related to an assembly of front and rear alpine ski binding elements, as well as an alpine ski, equipped with such a device.
2. Description of Background and Relevant Information
Skis used in alpine skiing are constituted by relatively long beans, on which the boots of the skier are retained by front and rear binding elements. The boots and binding elements are located approximately in the median zone of the ski, commonly known as the middle sole. At rest, the skis themselves have a natural arch, whereby the middle sole is naturally raised with respect to the front end of the ski, or shovel, and the rear end of the ski, or tail. In addition, the skis have a flexibility that depends on their internal structure. While skiing, the ski deforms elastically in response to the various forces to which it is subjected by the skier, as well as by the terrain over which it glides.
The main force to which the ski is subjected is constituted by the weight of the skier and the reaction to which the gliding surface subjects the ski.
The ski is also biased by the binding elements. In fact, it is known that the binding elements pinch the boot along a longitudinal direction. The reaction to this pinching action is transmitted by the binding elements to the ski. However, the nature of such reaction differs depending on the assembly mode of the rear binding element to the ski. Indeed, some rear binding elements are assembled directly onto the ski, whereas others are assembled to the front binding element by an inextensible connection, such as a metallic blade that extends beneath the boot.
The ski is also influenced by the position of the skier over his or her boots, depending on whether the skies carries his or her weight towards the front or towards the rear.
It is known that the behavior of the ski on the snow can be changed, especially its ease of turn initiation, its operational quality in turns or in a straight line, by influencing the arch of the ski, or by varying the longitudinal pressure distribution of the ski on the snow. By playing with such pressure distribution, it is known that the ski can be rendered more or less pivotal or more or less guiding, i.e., one can promote its ability to turn easily, and to have substantial operational stability. For skis that are currently on the market, the pressure distribution of the ski on the snow is mainly determined by the internal structure of the ski, and by the assembly mode of the binding elements to the ski, i.e., with or without connection blade between the front and rear binding elements. The distribution of pressure can also be influenced by the thrust intensity provided to the return springs.
There are devices with an attached element that enable the pressure distribution of the ski on the snow to be modified. As such, European patent application No. 183,586 describes a blade made of an elastic material of the spring blade type attached above the ski, between the binding elements and the ski. In the area of the front and rear ends, this blade has cursors whereby a portion of the forces to which the ski is subjected is transmitted vertically. However, this device has the disadvantage of mediocre performance with substantial space requirements. It is adapted for the case where both feet of the skier are in support on the same ski, in order to avoid the entire weight of the skier from being concentrated in the middle sole zone. On the other hand, it is ill-adapted in the case of a pair of conventional skis.
In accordance with the European patent application No. 409,749 applicants are also aware of a device constituted by a plate that is raised with respect to the upper surface of the ski maintained between two longitudinal abutments. Elastic shock absorption means are inserted between the plate and the abutments, and the pre-stress exerted on such elastic means is adjustable. As for the bindings, they are mounted on the plate. This device provides satisfactory results but its disadvantage lies in the fact that the binding elements are affixed to the attached plate and not to the ski itself. Other devices of the same type are described for example, in U.S. Pat. No. 2,560,693, and German patent No. 2,259,375.
With regard to these devices, it need only be said that the influence that they exert on the flexion of the ski is of a static type, i.e., they do not take into account the position of the skier on the skis while gliding.